| UPF | universal proximal femur [prosthesis] |
|---|---|
| UPIN | universal physician identifier number [HCFA] |
| USI | universal serial interface; urinary stress incontinence |
| BAP | bacterial alkaline phosphatase; Behavior Activity Profile; beta-amyloid peptide; blood-agar plate; b... |
| BBB | blood-brain barrier; blood buffer base; bundle-branch block |